1. Field of the Invention
The present invention relates to a vehicular seating apparatus usable for a vehicle such as a cab-over type vehicle or the like including a seat mounted above a service hole of an engine deck raised at the central part of a floor.
2. Prior Art
Many conventional cab-over type vehicles are constructed as follows. Namely, an engine deck including a plurality of wall portions is raised up at the central part of a floor constituting the bottom of a driver cabin, an engine, a radiator and other associated components are arranged below the engine deck, a driver's seat and an assistant driver's seat constituting front seats are arranged in a side-by-side relationship in the direction of the width of the vehicle (hereinafter referred to as the transverse direction), and a service hole is formed in the ceiling portion of the engine deck for the purpose of performing inspection and maintenance for the engine, radiator and so forth. The front seats such as the driver's seat, assistant driver's seat or the like can be turned backwardly or otherwise leaped up or moved up forwardly. When the front seats are displaced in that way, the service hole is exposed to the outside, enabling the engine, radiator and other associated components to be inspected and maintained, as required (refer to, e.g. Japanese Laid-Open Utility Mode NO. 102532/1984).
Recently, such a structure that a driver cabin is united with a cargo room and an assistant driver's seat situated by the side of a driver's seat is eliminated so that a driver can walk directly in the interior of the cargo room without need for him to descend from the vehicle has been employed for some cab-over type vehicles. This type of vehicle is called a walk-through type vehicle which is widely employed as a vehicle for collecting and delivering personal cargos from house to house.
However, the walk-through type vehicle has a drawback that an assistant driver can not ride thereon as an assistant for the driver due to elimination of an assistant driver's seat and thereby the degree of effective utilization of the vehicle is restricted within a substantially reduced range. On the other hand, a conventional cab-over type vehicle including an assistant driver's seat has the drawback that the driver can not enter the interior of the cargo room without the necessity of leaving the vehicle unless he performs an inconvenient operation such as climbing over his seat.
Generally, front seats arranged in the interior of a driver cabin of a vehicle can be adjusted in response to a request by a passenger with respect to their position in the forward/backward direction (hereinafter referred to as the longitudinal direction). In addition, each of the front seats is equipped with a seat belt for the purpose of assuring safety. One end of the seat belt is joined to a seat belt anchor secured to the vehicle at a predetermined position on the floor so that a load exerted on the seat belt is sustained by the floor. However, when the front seats are displaced to adjust their position in the longitudinal direction, the result is that a position which has been occupied by the front seat is relatively offset from the seat belt anchor secured to the predetermined position on the floor of the vehicle, causing the fitting characteristic of the seat belt to be degraded.
To obviate the foregoing problem, there was proposed a seat slide unit as disclosed, e.g. in Japanese Laid-Open Utility Model NO. 56124/1986. The seat slide unit is so constructed that a bracket for fitting a seat belt anchor is secured to the side portion of one of upper rails attached to a seat cushion and slidably engaged with lower rails fixed to the vehicle. U-shaped bent parts are formed on the lower edge of one side portion of the bracket and inverted U-shaped bent parts are formed on reinforcement rails attached to the lower rails to that the inverted U-shaped bent parts are slidably engaged with the U-shaped bent parts formed on the bracket for fitting the seat belt anchor. A relative offsetting of the seat cushion secured to the upper rails from the bracket for fitting the seat belt anchor is eliminated even under a condition that the seat cushion is displaced in the longitudinal direction, by allowing the bracket for fitting the seat belt anchor to be displaced along with the seat cushion when a position to be assumed by the seat is adjusted by displacing the seat cushion in the longitudinal direction while maintaining an improved fitting characteristic of the seat belt. Moreover a load exerted on the seat belt is reliably sustained by the vehicle via both the bent parts.
With respect to a cab-over type vehicle, such a need that displacement of the front seat as mentioned above is multi-directional so as to permit a passenger to move from a driver cabin directly into a cargo room situated behind the driver room hitherto has been raised by users. To this end it is required that displacement of the front seat by multi-directional and that a load exerted on the seat belt is then reliably carried by the vehicle without any degrading of the fitting characteristic of the seat belt of the front seat.